The present invention is directed to electrical test probe, and more specifically to a miniature electrical test probes suitable for use with both surface mounted and lead-mounted electrical components.
As the size of electrical components decreases, it becomes progressively more difficult to place electrical test probes on the leads of these components. Presently, electrical probe bodies typically are formed from injected molded plastic and are of a size that does not permit the attachment of multiple such probes to integrated circuit (IC) leads spaced on 0.050 inch centers. Attempts to decrease the diameter of the elongated nose portion of a typical probe along with the overall size of the probe body produce an increase in the internal electrical resistance of the probe. This is due to the decreased cross-sectional area of the conductive elements within the probes.
One example of a prior art electrical probe intended for use in probing IC leads is the "IC grabber tip" sold by Tektronix, Inc. as part number 020-1386-00. This prior art probe has a molded plastic body with a hollow elongate nose portion housing an axially movable conductor wire. A hook formed at one end of the conductor is used for "grabbing" an IC lead. A biasing spring connected to the conductor wire at the end opposite the grabber tip retracts the grabber tip into the probe body when it is not connected to an IC lead or other device. The size of the molded probe body is to large to permit placement of several such probes on adjacent leads of a small IC package. In addition, the internal resistance of this prior art probe design is in the hundreds of milliohms, a level that is detrimental to accurate signal acquisition and measurement.
What is needed is an electrical test probe that has substantially reduced internal resistance while at the same time is small enough to permit the connection of multiple probes to adjacent leads of miniature electronic components, such as surface mounted devices and integrated circuits.